An electric motor with a 1200 hp output drives a machine with an efficiency of 60%. What is the energy output of the machine per second?

536,904 J/s

Explanation:

The energy output from motor is the input energy in the machine.

We know that efficiency is percentage energy ouput to energy input, and expressed as

Where n and E represent efficiency and energy respectively, subscripts o and i represent output and input respectively. Since for the machine we have the input energy then the output will be the product of efficiency and input energy

Energy output=0.6*1200 hp=720 hp

Converting hp to J/s we multiply by 745.7

Energy is 720*745.7=536,904 J/s

u=13

v=30

s/t=u+1\2at

=13+431/2

=13+265.5

=278.5

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.